Efficacy Testing for Pesticides Targeting Certain Invertebrate Pests
The information provided below is intended to help pesticide registrants or applicants for registration complete the efficacy requirements related to pesticides intended to combat invertebrate pests.
- Pesticide Product Performance Data Requirements for Products Claiming Efficacy Against Certain Invertebrate Pests
- Efficacy label claims and associated efficacy testing
- Experimental design for efficacy studies
- Efficacy data and protocol submission
The FAQs Q&A’s listed below are related to the regulations located in Subpart R in 40 CFR part 158. These regulations contain product performance data requirements that must be submitted to support pest-specific claims for certain invertebrate pests of significant public health or economic importance.
Pesticide Products Performance Data Requirements for Product Claiming Efficacy Against Certain Invertebrate Pests
Where can I find information on requirements for invertebrate efficacy testing, including which pests to test to obtain certain labeling claims and what product performance standards must be met?
These requirements can be found in the regulations published by the Agency in Subpart R in 40 CFR part 158.
Information in Subpart R in 40 CFR part 158 “Product Performance for Products Claiming Effectiveness Against Invertebrate Pests,” conflicts or is inconsistent with EPA's Harmonized Test Guidelines for Invertebrate Product Performance. Which instruction takes precedence?
The regulations at Subpart R in 40 CFR part 158 supersede any guidance in the guidelines or pesticide registration notices (PRN) applicable to invertebrate public health pests, including any guidance relating to which species to test or performance standards stated. Note that the guidelines provide other guidance for conducting acceptable tests, including relating to test methods and reporting of data.
Subpart R in 40 CFR part 158 includes requirements for species-specific data for some pest claims. If my product has an atypical use pattern that would make obtaining data for a specific species impossible or inappropriate, are those data still required?
On a case-by-case basis, data requirements identified in subpart R may be adjusted for novel technologies or atypical use patterns that would make a particular data requirement inappropriate and not useful in the Agency's evaluation of the product. A waiver request must be submitted to adjust these standards, and such waiver requests will be given their own unique MRID numbers (see 40 CFR § 158.1707 and 40 CFR § 158.45). The request must clearly identify the data requirement for which a waiver is sought along with an explanation and supporting rationale for why the applicant believes the data requirement should be waived.
Applicants are encouraged to discuss a data waiver request with the Agency before developing and submitting supporting data, information, or other materials. The applicant may request a formal review of each study waiver under a PRIA submission (PRIA Fee Category R124, Conditional Ruling on Pre-application Study Waivers). It is important to note that a decision on the waiver request is conditional upon the review of the formal registration application and the data accompanying the application. Formal decisions or formal feedback on study waivers will not be made in any other pre-registration meeting with the Agency.
I completed a study and obtained product performance efficacy data. My data did not meet the performance standards for the identified target pest claims listed in Subpart R in 40 CFR part 158. I believe I can adequately justify the effectiveness of my product. What information should I submit?
On a case-by-case basis, EPA, in its discretion, may modify performance standards (e.g., 90% efficacy) as described in 40 CFR § 158.1707. The Agency will review an applicant’s written request to modify performance standard for specific products. Per the requirements of 40 CFR § 158.45, the submitted request must include, at a minimum, a clear identification the data requirement(s) for which modification is sought, a detailed explanation and supporting rationale for why the applicant believes the data requirement should be waived for the product, and efficacy data for all unsuccessful attempts to generate the data. Typically, an applicant’s desire to forgo testing would, on its own, be insufficient rationale to modify a data requirement.
This guidance is not binding on either EPA or any outside party, and the EPA may depart from the guidance where circumstances warrant without prior notice. Registrants may propose alternative approaches to the recommendations in this guidance, and EPA will assess them for appropriateness on a case-by case basis.
What efficacy data should be provided to support a “knockdown,” “quick kill” or “kills on contact” claim?
To make “knockdown,” “quick kill” or “kills on contact” claims, data should be provided that show:
- knockdown within 10 seconds for stinging Hymenoptera (including fire ants) or within 30 seconds for all other arthropods; and
- mortality by 96 hours post-treatment.
In addition, similar claims may be made with a time qualification (e.g., “kills quickly within 10 minutes”) if data show:
- knockdown at the labeled time qualification; and
- mortality by 96 hours post-treatment.
Under both scenarios, treatment groups should be statistically different from control groups, and control mortality should remain ≤10%. For product performance standards for knockdown and mortality, see the requirements at Subpart R in 40 CFR part 158.
What substrates should be tested to support residual efficacy label claims?
The choice of substrate is dependent on the labeled sites and claims:
- If a product is intended for use as an indoor residual treatment, both a porous (unpainted/unfinished ¼" thick plywood) and a nonporous (glazed ceramic tile) should be used.
- If fabric, mattresses, or carpet are included as a labeled site, efficacy data using cotton sheeting, mattress ticking and/or carpeting should also be provided.
- If a product is intended for use on buildings or as an outdoor residual perimeter or exterior crack and crevice treatment, a non-porous surface (vinyl siding or tile) and a porous surface (unpainted/unfinished ¼" thick plywood or unpainted concrete) should be used in product performance testing; if relevant to the labeled use patterns, concrete should be used instead of plywood.
- If a product is intended for use only on pavement, a porous surface (unpainted concrete) should be used.
- If a product is intended for use on trees, shrubs, hedges, etc., recently collected leaves should be included as a test surface. The plant species tested should be easily propagated and common in the areas where the product will be used. Leaves should be clipped from the treated plant as close to the exposure period as practical.
Treated surfaces should be stored outdoors such that they are exposed to direct sunlight and precipitation. Indoor aging regimes with simulated outdoor conditions should include diel cycles of photoperiod with a light source containing both UVA and UVB and periodic simulated rain, in addition to considering appropriate temperature and relative humidity. Regardless of whether the aging takes place outdoors or is simulated in the laboratory, the conditions used should mimic those under which the product would typically be used.
Please see the revised Product Performance Test Guideline OSCPP 810.3500 Premises Treatment.
What life stage should be tested to support efficacy claims for a pest if no life stage is specified on the label?
If a proposed labeling claim specifies a pest but not a particular life stage (e.g., "kills fleas"), adults should be used to obtain the claim.
How do I test the efficacy of pet products such as spot ons, collars and shampoos?
Recommendations on the design and execution of studies to evaluate the performance of pesticide products intended for use against invertebrate pests of pets, such as fleas, ticks, and mosquitoes, can be found in Guideline OSCPP 810.3300: The Efficacy of Topically Applied Pet Products Against Certain Invertebrate Pests. For example, the guidelines offer recommendations on what data should be submitted to obtain swimming, shampooing, and waterproof claims; when pest counts should be taken during efficacy testing; what type of negative control should be used; and what application rate should be tested.
Should dead and moribund arthropods be combined to obtain a percent mortality calculation?
No. EPA does not consider knocked down or moribund arthropods to be dead (i.e., motionless even when probed).
The number of dead, knocked down, and live pests in each replicate should be recorded separately at each time point tested, as practically possible. At a minimum, for mortality calculation purposes, dead individuals should be recorded at the last time point tested or at 96 hours after the onset of application/initial exposure, whichever comes first. A mortality count should include only dead, but not knocked down, arthropods.
While moribundity is not used as an endpoint for efficacy studies, if moribund individuals in a study are to be counted and reported, a definition of moribund appropriate for the species tested should be provided in the study report; moribund individuals should not be considered dead or be part of a mortality count.
For testing the efficacy of direct sprays and residual deposits in the laboratory, how many replicates are recommended?
Unless otherwise justified by the results of a power vs. sample size analysis, balanced (equal number of treatment and control replicates) experimental designs using a minimum of five replicates of 15 individuals, seven replicates of 10 individuals, or 35 replicates of one individual for each treatment, species, and, if applicable, surface type are recommended for most studies. Due to potential pest availability challenges, 25 replicates of one individual may be an appropriate replication scheme for centipedes, spiders, and scorpions, although 35 replicates of one individual is preferred. The protocol should fully describe how sample size and replication were determined. Pseudo-replication should be avoided; for example, an experiment in which five petri dishes of insects are sprayed using one sweep of a single aerosol can should not be considered to have five replicates. For exceptions and additional information, please see the revised Product Performance Test Guideline OSCPP 810.3500 Premises Treatment.
Should geometric or arithmetic means be used when reporting efficacy results?
The Agency prefers the use of arithmetic means for efficacy studies. For many studies, counts are the true response variable (percent control is considered a transformed response variable), and count data are often discrete and follow a Poisson (or binomial) distribution, which are more accurately summarized using the arithmetic mean. This is especially true for studies where a set number of individual insects are tested.
Geometric means are more appropriate for continuous data that follow a log-normal distribution. If the geometric or other mean will be used to summarize the data, then evidence that the data follow an appropriate distribution should be provided to show that the statistic is valid.
Note that an alternate reporting approach is recommended for pet products; see guideline OSCPP 810.3300: The Efficacy of Topically Applied Pet Products Against Certain Invertebrate Pests.
Yes. Test specimens should be transferred to clean containers after pesticide treatment because continuous exposure to a pesticide treatment is not a realistic scenario in most cases (one exception is treatment of immobile life stages (e.g., eggs)):
- For direct application studies (i.e., the specimen is treated directly with a pesticide), specimens should be transferred to clean containers as soon as practical but no more than 15 minutes after onset of exposure to pesticide application.
- For residual application studies (i.e., a surface is treated with a pesticide and the specimen is subsequently exposed to the treated surface), length of pest exposure to treated surfaces should be minimized and mimic real-world exposures based on the species tested. Crawling pests should be exposed to treated panels for no more than four hours. Flying pests should be exposed to treated panels for no more than one hour.
Please see the revised Product Performance Test Guideline OSCPP 810.3500 Premises Treatment for exceptions and more information.
Under what circumstances should an efficacy protocol be submitted and what information should be included in the draft protocol?
For non-guideline or other innovative experimental designs, novel products, or uncommon labeling claims, protocol submissions are helpful to assure registrants that their proposed methods are scientifically sound and able to produce reliable data to support their desired claims. Review of such protocols also helps ensure that test results would conform to current scientific standards.
Registrants should submit detailed descriptions of their objectives, experimental design for meeting such objectives, and discussion of appropriate data analysis so that a reviewer could perform the experiment by following the methods described in the submitted protocol. In addition, proposed labeling claims or a draft label should be submitted with the protocol.
For research involving intentional exposure of human subjects, study protocols must be submitted for joint review by EPA and the Human Studies Review Board (HSRB) and be approved prior to performing the studies in accordance with EPA’s regulations (40 CFR part 26).
EPA also encourages the development of new approach methodologies (NAMs) to reduce testing using vertebrate animals. Protocols proposing new approach methods, especially those methods which do not rely on utilizing vertebrate animals for testing, should be submitted to EPA for review before the study begins.
What raw data should be submitted with efficacy studies?
40 CFR §160.3 describes the Agency’s definition of raw data. Generally, to review an efficacy study, efficacy reviewers should have:
- count data for treated and control replicates (including data sheets); and
- statistical analyses.
Is there any information that can be included in an efficacy submission cover letter to facilitate the review of the efficacy package?
A clear cover letter explaining the intent of the submission assists in the timely review of efficacy data. Here are examples of information that is helpful to include in the submission cover letter:
- If the submission is related to a prior action and relevant details (e.g., whether an associated protocol was reviewed by the Agency under PRIA and if the new data being submitted are intended to address a deficiency identified in a prior review) — include MRID numbers of previously reviewed studies and protocols;
- If and when an efficacy study design guidance related to the submission was given outside of a formal PRIA protocol review (e.g., during pre-submission meetings, through email or a phone call, etc.);
- The list of pests for which data are being submitted, to assist in confirmation of the correct PRIA code;
- What specific pest, marketing claim, and/or use pattern each submitted MRID is intended to support; and
- If data bridging is being requested, and if so, which registered product is being cited for labeling claims and efficacy data.
- If a waiver request is being submitted for one or more of the data requirements listed in Subpart R in 40 CFR part 158.
Should a crosswalk be provided for the tested formulation and rate compared to the proposed or registered pesticide product formulation and labeled rate?
When submitting an efficacy data package, including a crosswalk describing how a tested formulation and/or rate compares to a proposed or registered product formulation and/or labeled rate can be particularly helpful in determining the acceptability of a study to support proposed labeling if:
- the tested formulation is different than the proposed/registered formulation;
- the tested formulation is the same but is identified in the study report under a different title/designation compared to the proposed/registered product name; and/or
- the tested rate and proposed/registered product labeled rate are not identical or in the same units.
Should each efficacy study receive its own unique master record identification MRID number?
Yes. When submitting multiple studies within a single submission, each study (i.e., single methodology) should have its own MRID number. For example, a direct spray test using multiple species may be submitted under a single MRID number, but a direct spray test and a residual test should be submitted under separate MRID numbers.
If a submitted study methodology deviates from a previously approved protocol or from the way it is described in 810 series product performance test guidelines, is it helpful to include a short justification for the deviations?
Yes, it is helpful to include a short justification with the scientific rationale for these deviations because it can assist the science reviewer in determining the acceptability of the study. To justify deviations from performance data standards or species testing requirements, see Pesticide Product Performance Data Requirements for Products Claiming Efficacy Against Certain Invertebrate Pests. This document includes information about the submission of a waiver request.
If you have questions, send us an email OPP_RD_INVERT_EFFICACY@epa.gov.